Why Do Flat Roofs Have Rocks On Them

But such a low slope holds snow and water much longer than a steeply pitched roof and therefore needs a very different material to stay watertight.

Why do flat roofs have rocks on them.

Because the gravel holds and releases heat the layer of gravel on a bur flat roof can both help water evaporate and keep heat away from the underlying roof structure. Flat roofing is not actually flat. Ideally the stones are river gravel which has smooth edges and won t cut into the roof when somebody walks around on it. The gravel provides a better grip for foot traffic when conducting maintenance or repairs.

This is for a roofing membrane that is not fully adhered to substrate and the pebbles are essentially acting as a paperweight. If the roof is what is called a ballast roof it is not fastened or adhered down throughout the whole roof. A flat roof is a roof which is almost level in contrast to the many types of sloped roofs the slope of a roof is properly known as its pitch and flat roofs have up to approximately 10. It has a very low slope between 1 4 to 1 2 inch per foot so that it drains water.

Roofing ballast is usually the little pebbles you see on a flat ish roof. Talk to ten roofing contractors and you ll get ten answers on what the gravel is for but this seems to be the consensus.